Having recently completed a new play-through I thought I would provide some feedback on the Companions. I will list them in the order of "issues".
Lae'zel
I like the characterization of Lae'zel. I view her as a aspiring, straight lined, fake it 'til you make it career pro. Ready to toe the company line, ready to feel slighted if ignored or not given deference, and ready to give a little loyalty back if you're helping push what she wants to you push. Underneath it all she is still a novice that doesn't really know what she's doing, yet to realise the world isn't quick as black and white as she's told it is. This is her first big journey from home and a coming of age journey for her, but this might not be clear to other companions and the PC right up front. I feel that she's got a lot of scope for interesting growth, conflict, and surprises and I want to have her in the party to see what that involves.
The big problem with Lae'zel is that if your PC goes along with her, if you're not playing a character that can see beneath her mask from the get go, she drives you into areas that game doesn't actually... want you to go yet. Her insistence on two particular points are problematic:
1 - Pushing hard and not resting. A PC that thinks LZ knows the most in the party about Mind Flayers, which is credible given the Gith history, will resist any long rests because they think time is of the utmost importance to avoid transformation. The suggestions others have to offer that we have more time that we think is off-set by LZ insistence, and if you go with her (which is probable for many parties that choose to have her) then you will deliberately avoid the long rest activity by which much of the early narrative of the game is driven. This is a problem.
2 - Following on directly from #1 is the Gith fight, in that a belief in LZ would mean a commitment to the Gith creche as the best possible course of action, leading you quickly to the Gith fight where you are under-leveled and likely to die. If somehow you don't die, then you actually get a plot direction to continue to leave the area, skipping most of the content the game presents there. Both of these are problematic from a narrative perspective, as they require you to make decisions from a meta-game perspective, rather than consistent with the story the game presents you, or you just.. miss most of the game.
I think both of these things can be handled better fairly easily but some tweaking around the edge of interaction with LZ in two directions:
A - Allow LZ to seem more ignorant/doubtful earlier, so the PC can question her and moderate the insistence she has with doubt/caution.
B - Allow LZ to demonstrate her own forceful pragmatism with regard to long resting.
Specifically in regard to the second issue, I think there's an out the game could present for groups that rush to the Gith fight:
1 - When arriving in the area allow the PC to question LZ's desire to confront the Gith (triggered being not having rescued Halsin yet, or the player level being too low), have LZ to go down alone stubbornly, have her own cut scene in which she in knocked out and left for dead and the Gith leave. Then have the player group come down, revive LZ and have her be awakened to a new sense of pragmatism - leading the group back to the Halsin and the rest of act 1.
Essentially the course is easy - get to the Gith fight too early and the game suggests you avoid it, or if LZ won't do that, gives you and her a big tourn-around epiphany. Get there later when appropriately leveled, then allow the experience to be a push forward angrily response, rather than the turn around one, leading naturally into the next stage of the game.
I quite like this idea, being that the time at which you take on the Gith fight provokes a different development response in LZ - either making her more doubtful and humble, or making her angrier and more insistent. Either is better than the current situation, where getting to the Gith fight too soon just doesn't make sense.
Wyll
I don't quite get Wyll. I believe he's meant to be trying really hard to be an actual good guy, but he's prone to violence, lacks any subtlety, and wears his secrets on his sleeve. He's trying really hard to be something, but has now become detached from reality a little in the effort. He's a charlatan that doesn't realise he's a charlatan.
The main problem for me is he break between how the PC and companions see Wyll, and how the NPCs see him. How can this guy, who can barely swing a sword, actually have renown and respect as a 'blade' hero?
There's the line of discussion between Wyll and Gale where they discuss both having lost a lot of their power, but there's nothing explicitly between Wyll and the player that addresses this AFAIK, and I think this is a big part of Wyll's problem. If there was more recognition that Wyll has somehow lost his "blade" powers, and is surviving on name alone for the time being, then he makes a lot more sense all of a sudden. Someone who was a genuine hero with a dark secret, arrogant and confident with it, having been brought low by the tadpole and being left just with his confidence and secret, and a fraction of his power.
The bones of this presentation are present in Wyll's story, but I think it needs to be dialed up a little to make it clearer to the PC and companions. It's ok that NPCs are still fooled, they've not been up close with him much. But the PC should be noticing this pretty quickly and questioning Wyll about it - not just his secret, but his power loss - much earlier than it happens in the game.
Which isn't to say Wyll has to respond any different at first - but letting the player more forcefully question him about what is clear in front of them is a no brainier for me. Instead when you talk to him he is in high spirits and talks about how he feels better than normal.
Then we get to his stats which everyone has observed are just all wrong for a melee folk hero. Unless there's some boost he gets from his patron that changes that significantly I don't get it. He should have better dexterity at the least? Why is his intelligence so high? A dude making deals with cambions surely isn't the smartest tool in the shed.
Minor point - How is he so integrated into the grove already? Was I out for a few days? Isn't everyone on the ship getting to the grove at around the same time if I'm heading straight there.
Gale
I think Gale makes sense, and is pretty consistent. The problem for me is he's too slow to get going, and is pretty uninteresting as a companion as a result.
He has a good enough entrance to the company, and has his stuff going on when he gets going. But he doesn't dig into the/his story quickly enough. SH digs in with the prologue and the beach and the artifact. LZ digs in with the prologue and the rescue and the creche. Wyll (tries) to dig in with the grove defense and the Goblin raid. Astarion digs in with the (poorly handled) introduction and the dead pig (enough to keep you going until he becomes hunted / tries to feed on you). But Gale just ... turns up and hangs around. Whatever you want to do, Gale seems mostly cool with it. He pops up with enough interaction, but he's a bit too aloof and collected to be really interesting.
Then when he does get going it's... all about Gale. There's not a lot of benefit for a party to have him along. He doesn't do anything special, he doesn't tie in strongly to the narrative, and he can be a little clunky to trigger for his own thing. Then, when he does, he just wants to eat stuff you find, and doesn't offer much in return.
Overall I think he would be pretty decent as a good companion if we have 4 or 5, but with just 3 it feels like a bit of a waste to have a guy who seems to have less going on, and doesn't bring as much to the world.
At least he doesn't do anything that feels wrong, though, like Wyll and LZ.
Astarion
I don't have many issues with Astarion, I think he's interesting enough, his story develops early enough to engage you, and you're given reasonable grounds to kill him or get rid of him if he doesn't suit your party also. For a good party it takes a little RP largess to see behind the curtain of this traumatized vampire spawn and give him enough credit to keep him, but that makes sense too.
Shadowheart
No issues with Shadowheart at all really. She's an interesting character. The evil on the surface but actually seems a decent person thing comes across pretty well. The only thing I would say is making it a little easier to interrogate her Shar worship if you miss some of the triggers in the game, because she isn't at all subtle about that and you shouldn't really have to pass a trigger to push it.
Karlach
If Karlach is a companion, and especially if she is a good aligned companion, then there needs a bit of work done on her recruitment quest. There's really not a lot of reason to believe shes the lesser of two devils, so if recruiting her is reliant on killing the false Tyr gang.. well it's not an obvious one for a good or even neutral group.
Overall
There's a general feeling that in order to open up a few of the stories of the companions you need them to like you.. which I really hope isn't a thing. I would expect triggers should vary between time, game events, as well as liking and disliking. Having too much of the character interactions tied to approval being high will probably make for a boring monoculture of a group, which is the least interesting type of group in my mind.